This invention relates to a method of purifying oil, and more particularly to a method of removing radioactive waste contaminants from lubricating oil.
Nuclear power plants, nuclear fuel reprocess facilities, and other types of facilities which handle radioactive material have serious problems in disposing of radioactive contaminated wastes such as lubricating oils, solvents, and antifreeze.
Lubricating oils are used in many areas of a nuclear power plant. They can be easily contaminated. Any spillage or leakage of lubricating oils from areas such as the turbine oil systems or feed water pumps goes to sumps and other drainage systems. The oil mixes with water and other contaminants from the nuclear reactor systems. Thus the lubricating oil becomes contaminated with radioactive wastes as well as dirt and moisture. Although the oil and water are not themselves radioactive, the other contaminants make the entire mixture radioactive.
The method most commonly used today by the nuclear industry to dispose of radioactive waste is to solidify and bury it. With oil based radioactive wastes emulsifiers and Portland cement are used to solidify the waste. This method of solidifying is acceptable to the Nuclear Regulatory Commission (NRC), but the process increases radioactive waste volume three to four times. Using this method on oil, one barrel of liquid oil will produce three to four barrels of solid waste. With the burial ground space allocation for radioactive waste decreasing so rapidly, a waste volume increase from one to four is barely tolerable. Another drawback with solidifying oil based waste is that the end product of the solidifying process is not guaranteed to be disposable. Oil mixtures often resist solidification even with emulsifiers.
What is needed is a way of reducing the end volume of processed radioactive waste. One way to do this for contaminated oil is to remove the actual radioactive contamination and processing it instead of treating the contamination plus the oil as radioactive waste.
The present invention offers a solution to the problem of increased volume when processing radioactive waste. The present invention is a method for removing radioactive contaminants from liquid radioactive wastes such as waste oil and reducing the radioactive waste volume by approximately 400 to 1. The radioactive waste resulting from this process is oil free and can be easily treated by the standard radioactive waste processing system. The resulting oil non-radioactive and can be recycled or used as fuel.
In one application of the present invention 660 gallons of radioactive contaminated waste oil was purified leaving a radioactive waste residue of 1.5 gallons of dry waste. The purified oil was radioactive-free as presently defined by the NRC.
Accordingly, an object of this invention is to provide a new method of removing radioactive contaminants from waste oil.
Another object of this invention is to provide a method of reducing radioactive waste volume in the processing of radioactive waste oil.
A more specific object of this invention is to provide a new method of removing radioactive pollutants from waste oil which includes removing particulates with heating and filtering, converting the remaining pollutants into salts, removing water from the oil, and filtering out all salts.
Other objects and advantages of the present invention will be apparent from a further reading of the specification and of the appended claims.